FINAL IK TUTORIAL - Custom IK Rigs

Introduction

This tutorial guides you through creating custom Inverse Kinematics (IK) rigs in Unity using the Final IK plugin. We will focus on the CCDIK (Cyclic Coordinate Descent Inverse Kinematics) and RotationLimit components, essential tools for achieving realistic character movements. Understanding these components will enhance your game development skills and improve character animations.

Step 1: Setting Up Final IK

• Ensure you have the Final IK plugin installed in your Unity project.
• Import the Final IK package into your project through Unity's Asset Store or by downloading it from the RootMotion website.
• Create a new GameObject in your scene where you want to apply the IK rig.
• Add the necessary components:
  • Select your GameObject.
  • In the Inspector panel, click on "Add Component."
  • Search for "CCDIK" and add it.

Step 2: Configuring the CCDIK Component

• After adding the CCDIK component, set up the necessary parameters:
  • Solver: Assign the GameObject that will be controlled by the IK system.
  • Target: Specify the target position for the end effector (e.g., a hand or foot).
  • Bones: Assign the bones of the character that will be affected by the IK.
• Adjust the Iterations setting for how many times the solver will adjust the joint angles. More iterations can lead to more accurate results but may impact performance.

Step 3: Adding Rotation Limits

• To prevent unnatural joint movements, add RotationLimit components:
  • Click on "Add Component" again and search for "Rotation Limit."
  • Assign it to the relevant bones that require limits (like shoulders, elbows, etc.).
• Configure the RotationLimit settings:
  • Set Min and Max angles to define the allowable rotation range for each joint.
• Test the limits by moving the target and observing the joint behavior.

Step 4: Testing the IK Rig

• Create a simple script to manipulate the target position:
  • In the Project panel, create a new C# script and name it "IKTest."
  • Use the following code to move the target with the mouse:

    using UnityEngine;
    
    public class IKTest : MonoBehaviour
    {
        public Transform target;
    
        void Update()
        {
            if (Input.GetMouseButton(0))
            {
                Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
                RaycastHit hit;
                if (Physics.Raycast(ray, out hit))
                {
                    target.position = hit.point;
                }
            }
        }
    }
    

• Attach the script to a GameObject in your scene and assign the target from the CCDIK component.

Step 5: Fine-Tuning Your IK Rig

• Adjust the CCDIK settings based on your character's performance:
  • Experiment with different iteration counts and bone assignments.
  • Test the RotationLimit settings to find the optimal angles for natural movement.
• Observe the character in play mode to ensure the IK behaves as expected.

Conclusion

You have successfully set up a custom IK rig using Final IK in Unity. By configuring the CCDIK and RotationLimit components, you can create realistic character animations that respond dynamically to the environment. Next steps could include exploring more advanced IK techniques or integrating other Final IK components to enhance your character control further. Happy animating!